(1) Field of the Invention
This invention relates to a binding device for binding the openings of bags or other materials. More particularly, the invention relates to a binding device for binding the openings of bags made of plastic films, regenerated cellulose films, netting or the like and other long articles by applying binding materials to them like ribbons and automatically twisting the binding materials.
(2) Description of the Prior Art
A large variety of bags are widely used for putting various things such as bread, green vegetables, and other granular or lumpy materials into them. When the opening of a bag containing some material is closed up, a ribbon-like wire-carrying cord is wound around the bag opening and the end portions of the cord are then twisted together.
In recent years, there have been proposed different types of apparatus to perform this twisting work mechanically. However, they are generally complicated in structure and operation, and in addition, malfunctioning and other troubles are liable to occur. Further, since the twisting force is relatively weak, the binding may be somewhat loose and the twisted binding material can be easily moved on the bag opening portion. Because of such defects, satisfactory results have not been obtained.
In the apparatus as disclosed in Japanese Patent Publication No. Sho. 41-6077 (1966) (corres. to U.s. Pat. application Ser. No. 341,954now abandoned), the tying work is done by converting continuous rotary motion into intermittent rotary motion by using a rotary disk and a program plate that are interlocked to an electric motor. However, the apparatus itself is large-scale and complicated, and since it is electrically powered, the places where it can be used are restricted and it cannot be easily transferred as desired.
The apparatus disclosed in Japanese Patent Publication No. Sho. 49-16759 (1974) (corres. to British Pat. No. 1,115,734) is also an electrically powered one and the tying work is done with a rocking crank that is interlocked to an endless chain, so that this apparatus is not be free from the disadvantages described above. Further, in the apparatus disclosed in U.S. Pat. No. 3,825,039, the feeding of binding cord, cutting of the cord and the tying of the cord around the opening of a bag are performed by the drive of an air cylinder, so that it is not free from the defects of the above described devices.
While, as described in U.S. Pat. No. 3,538,960 (corres. to British Pat. No. 1,264,993), a small portable binding device has been proposed, however, in this device, the feeding and cutting of a cord is done by a link mechanism and the twisting shaft is rotated by a tension cord which is attached to one end portion of the same link mechanism. With such a structure, malfunctioning and other problems are easily caused to occur so that the device cannot be satisfactorily placed in practical service.